38 ARKIV FÖR BOTANIK. BAND 1. 



noides Kze (the latter called xreptans», not reptans S\v.; see 

 above p. 30). 



Among these it is pretty easy to distinguish Tr. jnmcta- 

 tum by its venules of different thickness, which are for the 

 most part distinctly thicker towards the point. This species 

 will be mentioned below, at the end of this paper (fig. 30, 31). 



The rest of this small species at first appeared rather 

 easy to classify, and although they are of different outline, I 

 put them together as Tr. si^henoides Kze. But after examin- 

 ing them microscopically, I got into difficulties, because I 

 saw that besides their being of slightly different size, shape, 

 colour, etc., they include somewhat dissimilar types of vena- 

 tion, and on account of this difference, I cannot unite them 

 as one single species, according to the importance which we 

 must ascribe to the venation as a distinguishing mark for 

 species of ferns. 



I had first to decide, therefore, which of the forms be- 

 fore me I could identify with the old species Tr. sphenoides 

 Kunze (1834), beautifully illustrated by G. Kunze, Die Farrn- 

 kräuter, T. 88, F. 2, but many times mistaken, or rejected 

 altogether b}^ pteridologists. As Kunze has himself quoted 

 »Trich. reptans Hook, et Grev., t. 32» (not reptans Sw.!), which 

 is an excellent drawing, I have this to go by also, and guid- 

 ed by these illustrations, I think I have before me several 

 specimens, which 1 may give, with good reason, as the true 

 sphenoides; see my drawings, fig. 22 and 23. 



In this genuine sphenoides the venules are not very crowd- 

 ed, and especially much sparser than in Tr. pusillum Sw. 

 (fig. 21) and in mj Tr. myrioneuron (fig. 28, 29). There are 

 in the larger fronds a few stronger veins, like the midrib 

 (see also Tr. pusillum, fig. 21), each of them going to a lobe 

 and no doubt equivalent to those, which in Tr. hymenoides, 

 fig. 1, and its allies, form the midrib of each primary seg- 

 ment (Prantl's »wahre Nerven^ or genuine veins); but the rest 

 of the veins are very slender and all equal, both the longer 

 branches and the short interrupted (»spurious») veinlets. They 

 are separated from each other by several (4—5 or more) rows 

 of rather broad and open cells, fig. 24, 25 A, B. Only sterile 

 fronds can be called »flabellate^ (or subflabellate) in a certain 

 stage as to the venation, because they occur without any 

 distinct midrib in the upper half, see fig. 28, C. 



